Adsorption Capacity For Crystal Violet Research Articles

Capparis spinosa L waste activated carbon as an efficient adsorbent for crystal violet toxic dye removal: Modeling, optimization by experimental design, and ecological analysis

Textile dyes are dramatic sources of pollution and non-aesthetic disturbance of aquatic life and therefore represent a potential risk of bioaccumulation that can affect living species. It is imperative to reduce or eliminate these dyes from liquid effluents with innovative biomaterials and methods. Therefore, this research aims to highlight the performance of Capparis spinosa L waste-activated carbon (CSLW-AC) adsorbent to remove Crystal Violet (CV) from an aqueous solution. The mechanism of CV adsorption on CSLW-AC was evaluated based on the coupling of experimental data and different characterization techniques. The efficiency of the CSLW-AC material reflected by the equilibrium adsorption capacity of CV could reach more than 195.671 mg·g–1 when 0.5 g·L–1 of CSLW-AC (Particle size ≤250 μm) is introduced into the CV of initial concentration of 100 mg·L–1 at pH 6 and temperature 65° C and in the presence of potassium ions after 60 min of contact time according to the one parameter at a time studies. The adsorption behavior of CV on CSLW-AC was found to be consistent with the pseudo-second-order kinetic model and Frumkin's linear isothermal model. The thermodynamic aspects indicate that the process is physical, spontaneous, and endothermic. The optimization of the process by the Box Behnken design of experiments resulted in an adsorption capacity approaching 183.544 mg·g–1 ([CV]=100 mg·L–1 and [CSLW-AC]=0.5 g·L–1 at 35 min). The results of the Lactuca sativa seeds germination in treated CV (70%), adsorbent solvent and thermal regeneration (more than 5 cycles), and process cost analysis (1.0484 $ L–1) tests are encouraging and promising for future exploitations of the CSLW-AC material in different industrial fields.

Removal of Crystal Violet Dye from Aqueous Solutions through Adsorption onto Activated Carbon Fabrics

The removal of contaminants from aqueous solutions by adsorption onto carbonaceous materials has attracted increasing interest in recent years. In this study, pristine and oxidized activated carbon (AC) fabrics with different surface textures and porosity characteristics were used for the removal of crystal violet (CV) dye from aqueous solutions. Batch adsorption experiments were performed to investigate the CV adsorption performance of the AC fabrics in terms of contact time, temperature, adsorbate concentration and adsorbent amount. Evaluation of the thermodynamic parameters and the adsorption performance of the AC fabrics in ground water and sea water solutions were also carried out. Langmuir isotherm model, pseudo first and pseudo second order kinetics models were utilized to analyze and fit the adsorption data. The introduction of oxygen-based functional groups on the surface of AC fabrics was carried out through a nitric acid treatment. This oxidation process resulted in a significant reduction in the surface area and pore volume, along with a small increase in the average pore size and a significant enhancement in the CV adsorption capacity, indicating that the dye molecules are mainly adsorbed on the external surface of the carbon fabrics. The herein evaluated 428 mg/g adsorption capacity at 55 °C for the oxidized non-woven AC fabric is one of the highest adsorption capacity values reported in the literature for CV removal using AC materials. Thermodynamic studies showed that the adsorption occurs spontaneously and is an endothermic and entropy-driven reaction. Furthermore, pristine and oxidized non-woven AC fabrics displayed more than 90% CV uptake from sea water samples, underlining the great potential these fabrics possess for the removal of dyes from natural/multicomponent waters.

Waste‐Valorized Nanowebs for Crystal Violet Removal from Water

Lightweight, metal‐free, sustainable, and reusable adsorbent materials are of paramount significance in addressing the challenges of wastewater treatment. Accordingly, semi‐crystalline nanocellulose (NC) is extracted from tissue paper waste and used to modify polyacrylonitrile (PAN) to produce electrospun nanowebs with strand diameters from ≈180–300 nm. The incorporation of NC into PAN is confirmed by infrared and Raman spectroscopy and X‐Ray diffraction. When tested for crystal violet (CV) adsorption, NC‐modified PAN (20% NC@PAN) exhibits the highest CV removal capacity, achieving 91–94% removal over three cycles each, demonstrating exceptional recyclability. In contrast, unmodified PAN significantly decreases in CV adsorption capacity (from 59% to 48% in the third cycle), possibly due to an increased (≈36%) nanofiber diameter. The adsorption kinetics, exhibiting pseudo‐second order, interparticle (in between nanofibers) diffusion, and Elovich kinetic models emphasize the role of multilayer CV adsorption through reversible chemical interactions. Confocal micro‐Raman spectroscopy unveils a multifaceted CV adsorption mechanism, suggesting both surface and multilayer diffusion, with NC‐enhancing interactions. These findings demonstrate the potential of NC‐modified PAN nanowebs as effective and environmentally sustainable adsorbents for removing CV from aqueous solutions, suggesting promising practical applications.

Post-synthetic modification of a covalent organic framework via a thiol–ene reaction for improving fluorescence detection and removal of cationic crystal violet carcinogenic dye

Based on a thiol–ene reaction, a covalent organic framework containing olefins (COF-A) is modified with 2-mercaptoacetic acid to prepare COF-S-COOH for the first time, which greatly improves the sensing and adsorption capacity for crystal violet.

Raphanus caudatus biomass powder as potential adsorbent for the removal of crystal violet and Rhodamine B dye from wastewater

Abstract In this work, Raphanus caudatus (radish pod) leaves biomass was used as an adsorbent for the removal of crystal violet (CV) and Rhodamine B (RhB) dye from water medium. Adsorption process was performed by changing different adsorption factors such as adsorbent dose, agitation time, adsorbate concentration, pH and temperature to get maximum removal of dyes. It was observed that R. caudatus leaves biomass showed 48.7 and 19.0 mg/g value of adsorption capacity for CV and RhB dyes, respectively. High adsorption capacity value for CV was observed due to its less complex structure and small sized molecules as compared to the RhB dye molecules. Dyes removal process followed pseudo second order with the values of regression factor (R 2) found as 0.999 and 0.998 for CV and RhB, respectively. Values of R 2 were found as 0.999 and 0.998 for the removal of CV and RhB respectively while following the Langmuir adsorption isotherm model. It illustrates the single layered dye molecules adsorption over the homogeneous surface of the adsorbent. Value of enthalpy (ΔH°) was found as 11.983 and 12.28 kJ/mol for CV and RhB, respectively. It indicates endothermic nature of the process along with the increased entropy at the surface of the adsorbent during the process. Increase of salt concentration in adsorption medium caused the decreased percentage removal of dyes. Reported adsorbent also showed potential for the removal of toxic dyes from industrial wastewater.

Gamma‐sterilized cow‐dung for confiscation of triphenylmethane dyes from water bodies

AbstractThe purpose of this work was to adsorb the triphenylmethane dyes crystal violet (CV), brilliant green (BG), and malachite green (MG) from an aqueous solution using cowdung (CD) that has been gamma‐sterilized. FTIR, SEM, EDX, and TGA‐DTA advanced techniques were used to characterize CD. The material had a pHPZC of 6, and it was shown that the maximal monolayer adsorption capacities for CV (at pH 4.83), BG (at pH 4.53), and MG (at pH 3.75) were, respectively, 179.39, 172.28, and 111.62 mg g−1. The equilibrium results were completely described by the pseudo‐second order model and Langmuir isotherm. Using the van't Hoff and Arrhenius equations, thermodynamic parameters like ΔG, ΔS, and ΔH were computed. The exothermic nature of the process change is indicated by the fact that the adsorption of CV and BG increased with lowering temperature whereas the adsorption of MG increased with increasing temperature, as the process was endothermic. Curiously, the values of the adsorption capacity acquired using the column adsorption approach is very similar to those obtained using batch adsorption trials illustrating the CD's capacity for dyes adsorption.

Binary adsorption isotherms of methylene blue and crystal violet on mandarin peels: prediction via detailed multivariate calibration and density functional theory (DFT) calculations.

The multicomponent adsorption of synthetic dyes has great relevance in the treatment of effluents due to the complexity of the adsorbate-adsorbent interactions. Therefore, this study provides useful information about the adsorption capacity of methylene blue (MB) and crystal violet (CV) in a bioadsorbent (mandarin peels) in a single-component and competitive system using detailed multivariate calibration analysis. The PLS1 multivariate calibration model was used to quantify the adsorbates. In mono and two-component systems, the adsorption capacity of CV (1.26-1.36 mg g-1) was superior when compared to MB (0.925-0.913 mg g-1), characterizing synergistic adsorption for CV and antagonistic adsorption for MB. The Sips model was effective for describing single-component systems, suggesting that adsorption did not occur in the monolayer. For competitive adsorption, modified, unmodified, and extended models were used to understand the interactions between the dyes and the bioadsorbent. The modified Redlich-Peterson (MRP) model was effective in describing the behavior of the binary system, indicating that the interaction forces with the adsorbate were significant. Thus, the bioadsorbent showed promising results for competitive adsorption, thus being of relevance to the industrial sector. Density functional calculations were also performed to characterize the atomic interactions for the removal of both dyes on mandarin peels.

Biochar with enhanced performance prepared from bio-regulated lignocellulose for efficient removal of organic pollutants from wastewater

This work presented a novelty method for preparing lignocellulosic materials with reinforced performances, that is, the lignocellulose of corn straw was bio-regulated into cellulose, hemicellulose, and lignin via three types of microorganisms (Aspergillus niger, Myrothecium verrucaria, Trichoderma reesei) with cross treatment. Three different types of biochar were then prepared by the carbonization and combined alkali activation processes. The results showed that the great quantity of micro/mesopores endowed biochars ultra-high specific surface areas up to 2881, 2986, and 2878 m2 g−1. Biochars exhibited ultra-high maximum adsorption capacities for crystal violet (CV) and tetracycline hydrochloride (TC), which was higher than that of most adsorbents including the corn straw-based carbon and multi-walled carbon nanotube. After five cycles, the samples maintained a removal rate of over 70% for CV and over 60% for TC, proving their good potential for recycling. This study showed that the bio-regulation of lignocellulose was not only an effective method to develop materials with enhanced adsorption performances, but also provided a feasible idea for the comprehensive utilization of lignocellulose.

Enhancement of adsorption efficiency of crystal violet and chlorpyrifos onto pectin hydrogel@Fe3O4-bentonite as a versatile nanoadsorbent

The magnetic mesoporous hydrogel-based nanoadsornet was prepared by adding the ex situ prepared Fe3O4 magnetic nanoparticles (MNPs) and bentonite clay into the three-dimentional (3D) cross-linked pectin hydrogel substrate for the adsorption of organophosphorus chlorpyrifos (CPF) pesticide and crystal violet (CV) organic dye. Different analytical methods were utilized to confirm the structural features. Based on the obtained data, the zeta potential of the nanoadsorbent in deionized water with a pH of 7 was − 34.1 mV, and the surface area was measured to be 68.90 m2/g. The prepared hydrogel nanoadsorbent novelty owes to possessing a reactive functional group containing a heteroatom, a porous and cross-linked structure that aids convenient contaminants molecules diffusion and interactions between the nanoadsorbent and contaminants, viz., CPF and CV. The main driving forces in the adsorption by the Pectin hydrogel@Fe3O4-bentonite adsorbent are electrostatic and hydrogen-bond interactions, which resulted in a great adsorption capacity. To determine optimum adsorption conditions, effective factors on the adsorption capacity of the CV and CPF, including solution pH, adsorbent dosage, contact time, and initial concentration of pollutants, have been experimentally investigated. Thus, in optimum conditions, i.e., contact time (20 and 15 min), pH 7 and 8, adsorbent dosage (0.005 g), initial concentration (50 mg/L), T (298 K) for CPF and CV, respectively, the CPF and CV adsorption capacity were 833.333 mg/g and 909.091 mg/g. The prepared pectin hydrogel@Fe3O4-bentonite magnetic nanoadsorbent presented high porosity, enhanced surface area, and numerous reactive sites and was prepared using inexpensive and available materials. Moreover, the Freundlich isotherm has described the adsorption procedure, and the pseudo-second-order model explained the adsorption kinetics. The prepared novel nanoadsorbent was magnetically isolated and reused for three successive adsorption–desorption runs without a specific reduction in the adsorption efficiency. Therefore, the pectin hydrogel@Fe3O4-bentonite magnetic nanoadsorbent is a promising adsorption system for eliminating organophosphorus pesticides and organic dyes due to its remarkable adsorption capacity amounts.

Removal of dyes from water using Citrullus lanatus seed powder in continuous and discontinuous systems

The objective of this study is to develop a low-cost biosorbent using residual seeds of the Citrullus lanatus fruit for the removal of cationic dyes. Physicochemical parameters such as pH, adsorbent mass, contact time, and temperature were evaluated for their effects on dye removal. The biosorbent is composed of lignin and cellulose, exhibiting a highly heterogeneous surface with randomly distributed cavities and bulges. The adsorption of both dyes was most effective at natural pH with a dosage of 0.8 g L−1. Equilibrium was reached within 120 min, regardless of concentration, indicating rapid kinetics. The Elovich model and pseudo-second-order kinetics were observed for crystal violet and basic fuchsin dye, respectively. The Langmuir model fitted well with the equilibrium data of both dyes. However, the increased temperature had a negative impact on dye adsorption. The biosorbent also demonstrated satisfactory performance (R = 43%) against a synthetic mixture of dyes and inorganic salts, with a small mass transfer zone. The adsorption capacities for crystal violet and basic fuchsin dye were 48.13 mg g−1 and 44.26 mg g−1, respectively. Thermodynamic studies confirmed an exothermic nature of adsorption. Overall, this low-cost biosorbent showed potential for the removal of dyes from aqueous solutions.

Synthesis of a novel magnetically recyclable starch-based adsorbent for efficient adsorption of crystal violet dye

A novel magnetic starch-based adsorbent (MSBA) was synthesized from the copolymer solution of starch-grafted acrylic acid treated by an alkali homogeneous phase as the precursor and Fe3O4@SiO2 particles as raw materials. The feasibility of dye wastewater treatment was studied using crystal violet (CV) cationic dye as the model dye. The research results have indicated when the optimum condition kept the temperature of 308 K, CV concentration of 10 mg·L-1, pH of 9.0, the adsorbent dosage of 0.10 g, and the adsorption time of 50 min, 90.31% of the CV can be removed by the MSBA. In terms of the Langmuir isotherm model, the maximum adsorption capacity for CV was 49.10 mg·g−1. The magnetic saturation intensities of MSBA were 14.80 emu·g−1. The kinetics results showed that the adsorption process conformed to the first-order model and the rate-controlling step was determined by multiple stages. In addition, the adsorption isotherms displayed that CV adsorption was well fitted to the Langmuir model, and thermodynamic parameters depicted the spontaneous endothermic process. The adsorption mechanism of CV involved electrostatic interaction and hydrogen bonding. The adsorbents can be regenerated in ethanol solution and the removal efficiency remained at 83.04% even after five adsorption-desorption cycles. MSBA can be recovered with a magnet and only experience a 7.6% loss of adsorbent with each reuse cycle. These results suggest MSBA is a promising candidate adsorbent for dye wastewater treatment because of its excellent properties, including high adsorption efficiency, simple magnetic separation and reusability.

Textural properties and adsorption behavior of Zn–Mg–Al layered double hydroxide upon crystal violet dye removal as a low cost, effective, and recyclable adsorbent

The preparation of adsorbents plays a vital role in the adsorption method. In particular, many adsorbents with high specific surface areas and unique shapes are essential for the adsorption strategy. A Zn–Mg–Al/layer double hydroxide (LDH) was designed in this study using a simple co-precipitation process. Adsorbent based on Zn–Mg–Al/LDH was used to remove crystal violet (CV) from the wastewater. The impacts of the initial dye concentration, pH, and temperature on CV adsorption performance were systematically examined. The adsorbents were analyzed both before and after adsorption using FTIR, XRD, and SEM. The roughness parameters and surface morphologies of the produced LDH were estimated using 3D SEM images. Under the best conditions (dose of adsorbent = 0.07 g and pH = 9), the maximum adsorption capacity has been achieved. Adsorption kinetics studies revealed that the reaction that led to the adsorption of CV dye onto Zn–Mg–Al/LDH was a pseudo-second-order model. Additionally, intraparticle diffusion suggests that Zn–Mg–Al/LDH has a fast diffusion constant for CV molecules (0.251 mg/(g min1/2)). Furthermore, as predicted by the Langmuir model, the maximal Zn–Mg–Al/LDH adsorption capacity of CV was 64.80 mg/g. The CV dimensionless separation factor (RL) onto Zn–Mg–Al/LDH was 0.769, indicating that adsorption was favorable. The effect of temperature was performed at 25, 35, and 45 °C in order to establish the thermodynamic parameters ∆Ho, ∆So, and ∆Go. The computed values indicated exothermic and spontaneous adsorption processes. The study presented here might be used to develop new adsorbents with enhanced adsorption capabilities for the purpose of protecting the water environment.

Effective adsorption of crystal violet onto magnetic nanoparticles decorated bacteria: Kinetic and site energy distribution analysis

The discharge of crystal violet wastewater will cause extremely serious harm to the natural environment and human health, due to its certain toxicity and carcinogenicity. The adsorption characteristics and mechanism of crystal violet on magnetic nanoparticles decorated bacteria (Fe3O4 @bacteria) were investigated especially the adsorption kinetic, equilibrium, mass transfer mechanism, and site energy distribution analysis. With the initial concentration of crystal violet 40 mg/L, pH= 4, the addition of 0.003 g Fe3O4 @bacteria, after adsorption for 2 h under 25 °C, the static maximum adsorption capacity of crystal violet was up to 114.8 mg/g, which was 2.07 times that of Fe3O4 under the same conditions. Fe3O4 @bacteria could be recycled more than 6 times, also exhibited a 76.2% reduction in COD for actual dyeing wastewater. The adsorption data fitted well with the Temkin isotherm model, Elovich kinetic, and pseudo-second-order kinetic models. As for the mass transfer mechanism of the adsorption process, the IPD model was more suitable to describe the mass transfer process of the crystal violet adsorption by Fe3O4 @bacteria, while the intraparticle diffusion is not the only mechanism controlling the adsorption process. The adsorption process is spontaneous and exothermic according to the thermodynamics study. Based on the analysis of site energy distribution, the biosorbent had a heterogeneous surface and most of the crystal violet sorption occurred on the sites with energy over 13.0 kJ/mol, which supported that crystal violet sorption was physical-chemical sorption. Therefore, the magnetic nanoparticles decorated bacteria can serve as promising adsorbents to eliminate the organic dye pollutants caused by textile industry.

Engineered biochar prepared using a self-template coupled with physicochemical activation for highly efficient adsorption of crystal violet

In this study, engineered biochar (EBC) was prepared from rice husk biochar to achieve highly efficient crystal violet (CV) removal. EBCs have critically controlled the structures through the use of three strategies of conventional chemical activation, self-templating coupled with chemical activation and self-templating coupled with physicochemical activation. EBCs are characterized by SEM, EDS, BET, and FTIR. The batch adsorption experiments using kinetic and isotherm studies are applied to investigate CV adsorption. The hierarchical porous structure is only observed in samples prepared by the self-template method using naturally available SiO2 templates inside rice husk. By using the self-template coupled with physicochemical activation, EBC-3 is prepared with an excellent SSA and mesoporosity of 2344 m2 g−1 and 0.70, respectively. As a result, EBC-3 achieves a remarkably high maximum CV adsorption capacity (564.42 mg g–1) and rapid CV adsorption rate (0.035 g mg–1 h–1). The obtained results are due to the formation of a hierarchical porous structure with high mesoporosity, facilitating the transport of CV molecules. The large SSA and rich functional groups provide abundant active sites for CV adsorption. The CV adsorption on EBC was governed by pore filling, electrostatic attraction, π–π interaction and hydrogen bonding mechanisms.

Insight into adsorption mechanism, modeling, and desirability function of crystal violet and methylene blue dyes by microalgae: Box-Behnken design application

Herein, an environmentally friendly and efficient adsorbent of microalgae (MAG) was applied for the removal of crystal violet (CV) and methylene blue (MB) dyes from aqueous solutions. Multivariate modeling and optimization of CV and MB dyes removal onto MAG via Box-Behnken design (BBD) were investigated depending on three variables i.e. MAG dosage (20–100 mg), initial pH (4–10), and adsorption time (2–6 min). The adsorption kinetics and isotherm analyses revealed that the pseudo-second-order and Langmuir models governed the adsorption of CV and MB dyes onto MAG. The maximum adsorption capacity of MAG generated from the Langmuir equation was computed to be 243.0 mg/g for CV and 297.1 mg/g for MB. The determined thermodynamic parameters denoted that the adsorption mode of CV and MB dyes by MAG was spontaneous and endothermic. Several interactions like electrostatic forces, n-π stacking, and H-bonding caused the adsorption process of CV and MB molecules on the surface of MAG. The results showed that MAG could be an effective and locally available candidate adsorbent for removing dyestuffs from contaminated effluents. • Microalgae were applied for the removal of cationic dyes removal (crystal violet, CV) and (methylene blue, MB). • Box–Behnken design was applied to enhance the adsorption process. • The adsorption capacities for CV and MB were 243.0 mg/g and 297.1 mg/g, respectively. • The adsorption mechanism can be assigned to the electrostatic forces, n-π stacking, and H-bonding

Pyrolysis of rubber seed pericarp biomass treated with sulfuric acid for the adsorption of crystal violet and methylene green dyes: an optimized process

In this study, the biomass of rubber seed pericarp was first treated with sulfuric acid and then its activated carbon was formed by the pyrolysis process. As produced acid-treated activated carbon of chosen biomass was then used for the adsorption of crystal violet (CV) and methylene green (MG) from the colored aqueous solution. The adsorbent was exposed to several characterization methods to know its structural and morphological behaviors before and after CV and MG adsorption. The adsorbent was found to be mesoporous having a surface area of 59.517 m2/g. The effect of pH, time, and concentration was assessed while various isotherm and kinetics models were employed to know the adsorption insight. The optimum conditions were at pH 8, within 30 min, 50 mg/L concentration, and 0.06 gm dose. The adsorption data (the maximum adsorption capacity for CV and MG were found to be 302.7 and 567.6 mg/g, respectively) was validated by fitting in a response surface statistical methodology and the positive interactions between the studied factors were found. The adsorption was mainly belonging to the electrostatic attraction of the dye molecules. The study proves that the used adsorbent is economical and an excellent source of treating wastewater.

Effect of Chemical and Thermal Treatment Priority on Physicochemical Properties and Removal of Crystal Violet Dye from Aqueous Solution

AbstractThe release of pollutants, especially dyes, has been a significant concern as it affects the stability of ecosystems due to poor implementation of waste protocols. In this study, the diatomite samples were characterized by pHpzc, ICP, pore size distribution, XRD, TG‐DTA, BET, SEM and FTIR (before‐after). The adsorption properties of a cationically charged dye, crystal violet (CV), on the diatomite samples were investigated by varying the adsorption parameters with the aim of evaluating the adsorption mechanism. Nonlinear Langmuir, Freundlich, Dubinin‐Radushkevich and Redlich‐Peterson isotherm models, pseudo‐first and pseudo‐second order kinetic models, intraparticle diffusion and Boyd models were evaluated. The adsorption mechanism was explained by the Langmuir isotherm model and the maximum adsorption capacities for CV (at pH 7.0) of DHCl, D800 °C+HCl and DHCl+800 °C were 5.07 mg g−1 and 4.93 mg g−1 and 65.78. mg g−1 at 298 K, respectively. It was also shown that the CV adsorption was reasonable according to the second‐order kinetic model (R2=1). Adsorption occurred via two mechanisms: hydrophobic interactions and the combination of surface hydrogen bonding between the hydroxyl groups on the diatomite surface and the nitrogen atoms of the CV. The results indicated that using DHCl+800 °C would provide a simple, energy‐saving, and cost‐effective approach to removing cationic dyes from an aqueous solution.

Efficient removal of crystal violet from solution by montmorillonite modified with docosyl-trimethylammonium chloride and sodium dodecyl sulfate: modelling, kinetics and equilibrium studies

AbstractTwo novel modified montmorillonite (Mnt) components were prepared using Mnt nanoparticles and two surfactants: docosyl-trimethylammonium chloride (BTAC) and sodium dodecyl sulfate (SDS). These modified Mnts were used to remove a carcinogenic and harmful dye, crystal violet (CV), from solution. Optimization and modelling studies of the adsorption of these two modified Mnts were performed using response surface methodology. Four influential variables (concentration of adsorbent, temperature, pH and CV concentration) were studied to obtain the optimum conditions for CV removal. The optimal values of these variables for the two modified Mnts yielded 100% dye-removal efficiency. The optimum conditions for CV adsorption on Mnt-BTAC and Mnt-BTAC-SDS, respectively, are temperatures of 25.00 and 33.29°C, pH values of 9 and 10.1, CV concentrations of 50.00 and 10.44 mg L–1 and adsorbent concentrations of 1.00 and 0.98 g L–1. In equilibrium studies of the two modified Mnts, the Temkin isotherm was selected as an appropriate model, and in kinetic studies of these Mnts, the fractal-like integrated kinetics Langmuir model was found to be the best model. The Mnt-BTAC-SDS component is an affordable adsorbent with high adsorption capacity for CV.

Efficient removal of crystal violet by polyacrylic acid functionalized ZIF-67 composite prepared by one-pot synthesis

The adsorption of organic dyes by sorbents is one of the effective ways to resolve the problem of dye wastewater treatment. However, the limited adsorption capacity of adsorbents has always been a crucial factor that plagues the development and utilization of adsorbents. Herein, aiming at efficient adsorption for crystal violet (CV), polyacrylic acid (PAA) was incorporated into zeolitic imidazoline frameworks (ZIF-67) through an easy and environmentally friendly aqueous phase synthesis process at room temperature to synthesize adsorbent ZIF-67-PAA. Compared to pure ZIF-67, the obtained adsorbent ZIF-67-PAA showed excellent adsorption performance and the maximum adsorption capacity of CV can reach 1606 mg g−1. The adsorption process is spontaneous and conformed to the Langmuir isotherm model and the pseudo-second-order kinetic model. The results show that the prepared ZIF-67-PAA is a potential and efficient adsorbent for CV removal.

Adsorption Behavior of Crystal Violet and Congo Red Dyes on Heat-Treated Brazilian Palygorskite: Kinetic, Isothermal and Thermodynamic Studies.

The effect of heat treatment on the adsorptive capacity of a Brazilian palygorskite to remove the dyes crystal violet (CV) and congo red (CR) was investigated. The natural palygorskite was calcined at different temperatures (300, 500 and 700 °C) for 4 h. Changes in the palygorskite structure were evaluated using X-ray diffraction, X-ray fluorescence, thermogravimetric and differential thermal analysis, N2 adsorption/desorption and Fourier transform infrared spectroscopy. The adsorption efficiency of CV and CR was investigated through the effect of initial concentration, contact time, temperature, pH and dosage of adsorbent. The calcination increased the adsorption capacity of palygorskite, and the greatest adsorption capacity of CV and CR dyes occurred in the sample calcined at 700 °C (Pal-700T). The natural and calcined samples at 300 and 500 °C followed the Freundlich isothermal model, while the Pal-700T followed the Langmuir isothermal model. Adsorption kinetics results were well described by the Elovich model. Pal-700T showed better adsorption performance at basic pH, with removal greater than 98%, for both dyes. Pal-700T proved to be a great candidate for removing cationic and anionic dyes present in water.